Zhang Dong-Mei, Zhao Wen-Zhi, Luo Wei-Cheng
Linze Inland River Basin Research Station, Chinese Ecosystem Research Network, Key Laboratory of Eco-hydrology of Inland River Basin, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, No. 320, Donggang west Road, Lanzhou, 730000, China.
University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing, 100049, China.
J Plant Res. 2019 Jan;132(1):69-80. doi: 10.1007/s10265-018-01080-9. Epub 2019 Jan 4.
Clonal propagation is the main strategy for clonal plants to adapt to wind-sand habitat, and underground bud bank could reflect the potential ability of clonal propagation. However, the effects of population density on belowground bud bank are unknown, hindering efforts in the process of dune stabilization. We investigated the horizontal density and vertical distribution of belowground bud bank of a typical rhizomatous grass Leymus secalinus, and soil water content in four dune types with different population density (dune type I: 11.2 ± 1.7 no. m, type II: 24.2 ± 2.6 no. m, type III: 40.0 ± 4.0 no. m, and type IV: 53.5 ± 7.2 no. m) in Mu Us sandy land. Our results showed that (1) total bud density of population increased markedly with increasing population density, but it did not exhibit significant difference between dune types III and IV, where density was about 130 buds m; and tiller bud density of population first increased, then decreased, and reached a maximum in dune type III. (2) Total bud density per individual in dune type III was significantly larger than that in other dune types (P < 0.05), whereas rhizome and tiller bud density per individual did not show significant differences in dune types II, III and IV (P > 0.05). (3) Buds tended to be concentrated at 10-30 cm soil layer in all dune types, and be buried deeper in dune types III and IV than that in dune types I and II. (4) No pronounced relationship was shown between bud density and soil water content in 10-30 cm soil layer with increasing population density. Our results suggest that moderate population density (40.0 ± 4.0 no. m) significantly increase the bud bank density of L. secalinus population and individual. Soil water content was not the main factor responsible for the density of L. secalinus bud bank. These results can provide important information for implementation of effective sand fixation measures and species selection for desertification control in semiarid sandy land ecosystems.
克隆繁殖是克隆植物适应风沙生境的主要策略，而地下芽库可以反映克隆繁殖的潜在能力。然而，种群密度对地下芽库的影响尚不清楚，这阻碍了沙丘稳定化进程中的相关工作。我们调查了毛乌素沙地中不同种群密度（沙丘类型I：11.2±1.7株/m，类型II：24.2±2.6株/m，类型III：40.0±4.0株/m，类型IV：53.5±7.2株/m）的四种沙丘类型中典型根茎型禾本科植物赖草地下芽库的水平密度和垂直分布，以及土壤含水量。我们的结果表明：（1）种群的总芽密度随种群密度的增加而显著增加，但在密度约为130个芽/m²的沙丘类型III和IV之间没有显著差异；种群的分蘖芽密度先增加后降低，在沙丘类型III中达到最大值。（2）沙丘类型III中单个个体的总芽密度显著大于其他沙丘类型（P<0.05），而在沙丘类型II、III和IV中，单个个体的根茎和分蘖芽密度没有显著差异（P>0.05）。（3）所有沙丘类型中的芽都倾向于集中在10 - 30厘米的土层中，并且在沙丘类型III和IV中比在沙丘类型I和II中埋得更深。（4）随着种群密度的增加，10 - 30厘米土层中的芽密度与土壤含水量之间没有明显的关系。我们的结果表明，适度的种群密度（40.0±4.0株/m²）显著增加了赖草种群和个体的芽库密度。土壤含水量不是影响赖草芽库密度的主要因素。这些结果可为半干旱沙地生态系统中有效固沙措施的实施和荒漠化治理的物种选择提供重要信息。
